<?php
$arr = ["a", "b", "c", "d", "e"];

for ($i = 0; $i < count($arr); $i++) {
    echo $arr[$i];
};
echo "<hr>";
foreach ($arr as $item) {
    echo($item . "<br>");
};

$keyarr = [
    "user" => "张三",
    "pass" => "123456"
];
foreach ($keyarr as $key => $value) {
    echo "键=" . $key, "值=" . $value . "<br>";
};

$j = 0;
while ($j <= 100) {
    $j++;
    $str = $j."";
    $is = strstr($str,"7");
    if ($is) {
        continue;
    };
    echo $j."<br>";
};
while ($i <= 100) {
//    echo preg_match("/7/",$i);
    if (preg_match("/7/", $i) != 1) {
        echo "<br>", $i;
    }
    $i++;
}